Waves Breaking on Rocks by Peter Garland; selections from The Book of Sounds by Hans Otte; works by Terry Riley, James Cleghorn and othersSarah Cahill, recently called “that redheaded new music force of nature” in San Francisco Classical Voice, performs a program of summery piano music. A specialist in new American music, her program includes the Bay Area premiere of Peter Garland’s Waves Breaking on Rocks, selections from Hans Otte’s The Book of Sounds, and works by Terry Riley, James Cleghorn, and other Bay Area composers.